Production of artificial filaments



y 28, 1942. w. WHWE EAD 2,290,929

PRODUCTION OF ARTIFICI'Z L FILAMENTS Filed March 20 1940 INVENTORATORNEY5 Patented July 28, 1942' PRODUCTION OF ARTIFICIAL FILAMENTSWilliam Whitehead, Rye, N. Y., assignor to Celanese Corporation ofAmerica, a corporation of Delaware Application March 20, 1940, SerialN0. 324,965

4 Claims.

This invention relates to the manufacture of artificial or synetheticfilaments, and relates more particularly to a novel method of anapparatus for the manufacture of artificial or syntlietic filaments ofimproved textile character- 18 s.

In the manufacture of artificial or synthetic filaments from solutionsof cellulose derivatives in volatile solvents by methods in which thesolutions are extruded into a setting medium, the extruded filaments,either singly or associated together agflthreads, are led, with orwithout twisting, to bobbins or other winding supports or devices,located outside of the spinning cabinet on which they are wound.Heretofore the thread of associated filaments was led through aguidepositioned substantially at the opening leading from the spinningcabinet, passed through said opening, wound about a feed or godet rollerand finally wound on to a bobbin or like support, the feed or godetroller operating at such a speed that the filaments were drawn down orextended mor or less to produce filaments of increased strength and ofthe denier desired.

I have now found that cellulose derivative filaments of highly desirablecharacteristics may be obtained by extruding the cellulosev derivativespinning solution into the form of filaments and then collecting themwithout drawing them down. In accordance with my process, the extrudedfilaments are permitted to fall of their own weight whereby they areallowed to contract in length. The denier of the filaments formed by mynovel process will vary with the length of the cabinet or the length ofthe fall of the filaments. Thus, where the formed filaments fall througha greater distance the filaments have a greater unsupported length andthe weight thereof tends to stretch the same. Accordingly, filaments ofthe finer denier result.

' Furthermore, the denier of th filaments formed may be varied byvarying the size of the orifices in the spinnin nozzle.

Filaments produced in accordance with my invention have been found tohave increased strength and an elongation from '40 to 50% greater thanfilaments produced by prior methods, greater resiliency and greaterthermal insulating properties. Moreover, the filaments producedaccording to my novel process have a rougher surface longitudinallythereof than filaments made by prior processes, i. e. they have aplurality of continuous or irregular relatively deep indentations orcanals extending along the length thereof. Such rough surface filamentsare particularly suitable for the production of staple fiber since theyhave natural, inherent good spinning qualities and substantiallypermanent binding power, thereby obviating the necessity of putting acrimp in the same. Blankets, suitings and like fabrics made from suchstaple fibers are substantially free from shedding and have higherthermal insulating qualities presumably on account of the airspaces'between the deep striations in the filaments.

It is an important object of this invention to provide a process for theeconomic and expeditious manufacture of artificially produced filamentshaving increased strength and elongation, greater resiliency and greaterthermal properties than artificial filaments heretofore made.

Another object of this invention is the production of staple fibers ofimproved textile characteristics.

A further object of this invention is the provision of a simple,efiicient and inexpensive apparatus for producing the improvedfilaments.

Other objects of this invention will appear from the following detaileddescription.

In the accompanying drawing, wherein one embodiment of my invention isshown,

Fig. 1 is a diagrammatic representation of a portion of a metier withmeans for withdrawing the filaments therefrom, and

Fig. 2 is a detailed view showing the filaments being led to a devicefor converting the same into staple fiber.

Like reference numerals indicate like parts in both views of thedrawing.

Referring now to the drawing, the metier, which is generally indicatedby reference numeral 3, may contain any desired number of spinningnozzles l arranged in the upper part of the metier, each being formedwith a number of spinning orifices to form a corresponding number offilaments. While Fig.1 shows a metier having five compartments or cells5 separated from each other by vertical partitions 6 and each containingone spinning nozzle, it is to be understood partments or cells may bearranged in a row and that each of said compartments or cells have morethan one spinning nozzle. The spinning nozzles are, of course, suppliedwith the spinning solution from any convenient supply header, not

shown, and the metier is insulated in any suitable manner as is wellknown in the art.

The filaments I as they are formed are permitted to fall of their ownweight upon an endless conveyor belt 8, carried by pulleys 9 and II thatany suitable number of such comdriven in any suitable manner, whichconveyor belt removes the filaments from the metier. Since no tension isapplied to. the filaments they contract in length before meeting theconveyor belt 8. Preferably, the conveyor belt is arranged to travel ata linear speed equal to or less than the rate of speed at which thefilaments fall. The lower edges of the walls-of casing 3 should be asclose as possible to the conveyor belt 8 or otherwise so arranged as toadmit little external air.

A roller l2, which may be an idler and of any suitable size, ispositioned above the pulley H and with the conveyorbelt 8 acts as a niproller ar- 01 celllulose such as, for example, acetates of cellulosehydroxy ethyl-ethers may be employed.

-It is to be understood that the foregoing detafled description ismerely given by way of illustration and that many variations may be madetherein without departing from the spirit of my invention.

. Having described my invention, what I desire to secure by LettersPatent is:

rangement through which the collected filaments pass and are fedforward. Suitably spaced from the pulley, II and the roller l2 are niprollers l 3 and H which preferably rotate at a. peripheral speed greaterthan that of the roller I2 and the conveyor belt 8, whereby thefilaments in the /sliver l5 are caused to straighten out.

The nip rollers l3 and I4 feed the sliver into a coiling can It. Or thesliver may be wound upon a support by any suitable winding device.However, as shown in Fig. 2, a sliver I 5 may be passed. from theconveyor belt 8 towards a cutting device, generally indicated byreference II, by the agency of an ejector device generally indicated byreference numeral I 8,the sliver passing through the cone I! of theejector device and a blast of compressed air or other fluid admittedfrom the conduit to annular space 2|, which blast of compressed airdraws or sucks the filaments of the sliver through the apex of the conecarrying'the sliver to the cutting devices.

The cutting device comprises a, rota ing member 22 mounted on a rotatingshaft 23 and has any suitable number of plates or knives 24. Theseblades or knives cooperate with a stationary blade 25 mounted on a block28 which may be adjustable with respect to the rotating blades or knives24 by means of a screwbolt-fl. The

' cut staple made up is blown into a chute 28 and collected in asuitable receptacle not shown. If it is desired to app y a finish to thefilaments, it is preferable to apply the same while the filaments arestill on the conveyor belt.

My invention is particularly applicable to the production of artificialfilaments or staple fibers having a basis of cellulose acetate or othercellulose derivative produced by the dry or evaporative method ofspinning. Examples of other cel-- lulose derivatives which may form thebasis of the filaments or staple fibers are cellulose propionate,cellulose butyrate, cellulose aceto-propionate, celluloseaceto-butyrate, thiocarbamic and alkoxy alkacyl esters of cellulose,cellulose condensation products of cellulose with glycols or otherpolyhydric alcohols. Similarly ester-ethers 1. Process for theproduction of artificial filaments or threads, which comprises extrudingin a downward direction a spinning solution into a setting medium,permitting the formed filaments to fall of their own weight, without theapplication thereto of extraneous tension, on to a conveying surfacemoving at substantially the same rate of speed as the speed at which theformed filaments fall on to said surface and transportethers such asethyl and benzyl cellulose, and theing the filaments on said surfacefrom beneath the point at which they are extruded.

2. Process for the production of artificial filaments or threads, whichcomprises extruding in a downward direction a spinning solutioncontaining cellulose acetate and a volatile solvent therefor into anevaporative atmosphere, persetting medium and permitting the formedfilaments to fall of their own weight, without the application theretoof extraneous tension, on to a conveying surface moving at substantiallythe same rate of speed as the speed at which the formed filaments fallon to said surface, collecting the filaments from said surface in theform of a sliver and applying'a tension on said sliver to straighten thefilaments thereof.

4. Process for the' production of artificial filaments or threads, whichcomprises extruding in a downward direction a spinning solutioncontaining cellulose acetate. and a volatile solvent therefor into anevaporative atmosphere and permitting the formed filaments to fall oftheir own weight, without the application thereto of extraneous tension,on to a conveying surface moving at substantially the same rate of speedas the speed at which the formed filaments fall on to said surface,collecting the filaments from said surface-in the form of a sliver andapplying a tension on said sliver to straighten the filaments thereof. 7

